Tournaments are at the moment rare, so when you see one it will be later on. Most likely, and administrator will conduct and host the tournament. To conduct a tournament you must require the following things:

* A set amount of people to avoid "byes"* A bracket or list of players* Maps for players to agree on* One set of rules for the whole tournament* Time to conduct the tournament

For making a bracket/list of players I reccomend this program: ALG tournament MakerIts an easy way to make a bracket. Admins who host the tournament might give prizes so be sure to look out for new tournaments all the time.